JP2008089094A - Conduit liquefaction measure structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conduit liquefaction measure structure for preventing the liquefaction of a ground apart from a conduit. <P>SOLUTION: The conduit liquefaction measure structure is provided for preventing the flotation of a pipe body 2 and a manhole 3 connected to the pipe body 2 when a ground around the conduit 1 is liquefied. It comprises a communication hole 41 for communicating the inside of the conduit 1 provided in the shell of the pipe body 2 with the outside thereof, a water pipe 42 provided extending from the communication hole 41 to a ground under the conduit 1, and a filter material 43 for preventing the passage of sediment inside the water pipe 42. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a pipe liquefaction countermeasure structure for preventing the rise of a pipe constructed on the ground that may be liquefied by an earthquake.

  2. Description of the Related Art Conventionally, a floating prevention structure for preventing a manhole from rising due to excessive pore water pressure generated in ground liquefied by an earthquake is known (Patent Document 1).

The manhole disclosed in Patent Document 1 is provided with through holes provided with check valves on the side walls and the bottom plate, and when the pore water pressure in the ground around the manhole rises due to an earthquake, the manhole is passed through the through holes. It is possible to suppress the generation of excessive pore water pressure by the pore water flowing into the water.
JP 2006-124966 A

  However, the conventional anti-floating structure described above can suppress the generation of excessive pore water pressure when the ground adjacent to the manhole is liquefied, but it is liquefied when the ground not in contact with the manhole is liquefied. There is a possibility that the effect as a countermeasure structure cannot be exhibited.

  In other words, solidification materials such as cement bentonite may be filled around the manhole as a backfill material, but such solidification materials have a low hydraulic conductivity, and the ground around the solidification material liquefies. Even so, it is difficult to instantaneously release excess pore water pressure through the solidified material to the through hole. As a result, the manhole may rise together with the solidified material filled for backfilling.

  Therefore, an object of the present invention is to provide a liquefaction countermeasure structure for a pipeline that can prevent liquefaction of the ground away from the pipeline.

  In order to achieve the above object, the liquefaction countermeasure structure for a pipe of the present invention prevents the floating of at least one of a pipe and a human hole connected to the pipe when the ground around the pipe is liquefied. A liquefaction countermeasure structure for a pipe line, a communication hole that communicates the inside and outside of the pipe line provided in at least one outer shell of the pipe body and the human hole, and the communication hole from the communication hole to a lower ground of the pipe line It is characterized by comprising a water pipe that is extended and a filter material that prevents passage of earth and sand inside the water pipe.

  Here, it is preferable that a check valve is provided at an end portion of the water conduit on the inner side of the conduit.

  A plurality of apertures can be formed on the side surface of the water pipe.

  The pipe liquefaction countermeasure structure of the present invention thus configured is provided with a communication hole that communicates the inside and the outside with the outer shell of the pipe, and the communication hole that extends from the communication hole to the lower ground of the pipe. It has a water pipe.

  Then, when the pore water pressure in the ground below the pipeline rises, the pore water flows into the pipeline through the water conduit, and the generation of excessive pore water pressure is suppressed.

  For this reason, generation | occurrence | production of liquefaction can be prevented even if the ground apart from the pipe line is highly likely to liquefy.

  Further, by filling the inside of the water pipe with a filter material such as crushed stone, sand and the like can be prevented from flowing into the pipe along with the pore water.

  Furthermore, by providing a check valve at the end of the water conduit inside the conduit, leakage of water flowing through the conduit to the ground can be prevented.

  And the liquefaction of the lower ground of a pipe line can be prevented in a wide range by providing a some opening part in the side surface of a water flow pipe.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 is a diagram showing a configuration of a liquefaction countermeasure structure for a pipeline 1 according to the present embodiment.

  First, in terms of configuration, the pipe line 1 is mainly composed of a pipe body 2 that allows water to flow down and a human hole 3 that is substantially orthogonal to the pipe body 2 and communicates with the ground surface.

  This tubular body 2 is a cylindrical object used as an agricultural water supply pipe, a sewer pipe, and the like, and is formed by connecting a plurality of unit length pipes each having a receiving part and an insertion part.

  For example, a fiber reinforced plastic mortar (FRPM) pipe can be used for the pipe body 1.

  The pipe body 2 composed of this FRPM pipe is formed by integrating a resin mortar layer between an inner surface FRP layer and an outer surface FRP layer which are two fiber reinforced plastic (FRP) layers.

  The inner surface FRP layer and the outer surface FRP layer are formed by laminating a plurality of glass fiber layers whose fiber directions are in the circumferential direction or the tube axis direction and impregnating with unsaturated polyester.

  The resin mortar layer is made of an inorganic material such as cinnabar and an unsaturated polyester resin, and is integrated with the inner surface FRP layer and the outer surface FRP layer.

  On the other hand, the human hole 3 is a manhole formed in the tubular body 2 at predetermined intervals, and is used when entering the inside of the tubular body 2 for the purpose of maintaining and managing the conduit 1.

  Although FIG. 1 shows a structure in which the human hole 3 is erected on the upper surface of the tube body 2, the present invention is not limited to this. Good.

  And in the liquefaction countermeasure structure of the pipe line 1 of this Embodiment, the communicating hole 41 which connects the inside and outside of the pipe line 1 is provided in the outer shell of at least one of the pipe body 2 and the human hole 3.

  That is, in FIG. 1, two communication holes 41, 41 are provided on the lower side surface of the tubular body 2 located below the human hole 3 with the human hole 3 interposed therebetween. For the communication hole 41, a grout hole for grout injection provided in the tube 2 in advance can be used.

  1 is a backfill material 51 filled in excavation grooves excavated in a groove shape when the conduit 1 is installed. The backfill material 51 corresponds to cement bentonite in which cement is added to a stabilizing liquid such as bentonite used for protecting hole walls during excavation and solidified, and backfill soil in the case of dry excavation.

  Then, it is assumed that a liquefied layer 52 such as a loose saturated sand ground exists on the lower ground of the backfill material 51.

  In the present embodiment, the water pipes 42 and 42 are suspended from the communication holes 41 and 41 provided on the lower side surface of the pipe body 2 toward the liquefied layer 52.

  The water pipe 42 can be arranged on the lower ground of the pipe line 1 by inserting a vinyl chloride pipe, a steel pipe or the like from the inside of the pipe body 2 toward the ground.

  Further, as shown in FIG. 2A, a check valve 44 is provided at the end of the water conduit 42 on the inner side of the conduit. The check valve 44 is configured to be closed by the pressure of the fluid flowing inside the tube body 2 and to be opened when the water pressure inside the water flow pipe 42 becomes larger than the pressure.

  For example, FIG. 2A shows a state in which the communication hole 41 is located below the in-pipe water level 6A and is submerged. Normally, the check valve 44 is closed by the water pressure by the in-pipe water level 6A. Therefore, the water in the pipe body 2 does not flow out to the ground through the water pipe 42.

  FIG. 2B shows a structure that prevents the water in the pipe body 2 from flowing into the water conduit 42 by a configuration different from the check valve 44.

  In this structure, the communication hole 41 is provided on the upper side surface of the tube body 2, and a substantially L-shaped inner tube 45 connected to the human hole 3 from the communication hole 41 is provided inside the tube body 2.

  Since the upper end of the internal pipe 45 is located above the normal pipe water level 6B of the pipe body 2, the water in the pipe body 2 flows into the water pipe 42 without providing the check valve 44. There is no.

  Further, the passage of earth and sand is blocked by filling the inside of the water pipe 42 with a filter material 43 such as crushed stone as shown in FIG. Here, the structure of the water pipes 42A and 42B of two different forms was shown in FIG.

  The water pipe 42A shown in FIG. 3 (a) has a net lid 421 attached inside the vicinity of the lower end, and the filter material 43 such as crushed stone is laminated thereon, so that the filter material 43 flows downward. Can be prevented.

  3 (b) has a plurality of apertures 422,... Formed in the side surface, and the apertures 422,... Are embedded in the liquefied layer 52. By doing so, pore water in the liquefied layer 52 can be taken in from here.

  A net lid 421 is also attached to the lower end of the water conduit 42B, and a filter material 43 such as crushed stone is filled therein.

  Next, the effect | action of the liquefaction countermeasure structure of the pipe line 1 of this Embodiment is demonstrated.

  The liquefaction countermeasure structure of the pipe line 1 of the present embodiment configured as described above is provided with a communication hole 41 that communicates the inside and the outside with the outer shell of the pipe line 1 and from the communication hole 41 below the pipe line 1. A water pipe 42 extending to the ground is provided.

  Then, when the pore water pressure in the liquefied layer 52 below the pipe line 1 is increased by the vibration transmitted by the earthquake, the pore water whose pressure has increased through the water pipe 42 flows into the pipe line 1 and is discharged from the ground. Therefore, the generation of excess pore water pressure in the liquefied layer 52 is suppressed.

  For this reason, even if the ground away from the pipe line 1 is highly likely to be liquefied, it is possible to prevent the human hole 3 and the pipe body 2 from rising due to the liquefaction phenomenon. That is, even if the liquefied layer 52 is located away from the pipeline 1 with the backfill material 51 or other ground that is difficult to liquefy, the lower end of the water pipe 42 is embedded in the liquefied layer 52. By extending, generation | occurrence | production of liquefaction can be suppressed effectively.

  Further, by filling the inside of the water conduit 42 with a filter material 43 such as crushed stone, sand and the like are prevented from rising in the water conduit 42 together with the pore water. Can be prevented from flowing in.

  Furthermore, by providing the check valve 44 at the end of the water conduit 42 on the inner side of the pipe 1, it is possible to prevent leakage of water flowing through the pipe 1 to the ground.

  And the liquefaction of the lower ground of the pipe line 1 can be prevented in a wide range by providing the several opening part 422 ... in the side surface of the water flow pipe 42. FIG. That is, when the liquefied layer 52 is deposited thickly, the opening portions 422,... Are provided over a wide range in the depth direction of the water flow pipe 42 embedded in the liquefied layer 52, and the pore water is taken in a wide range. You should be able to.

  In the following, in this example, a liquefaction countermeasure structure of the pipe 71 in a form different from the above embodiment will be described with reference to FIG.

  In the above-described embodiment, the example in which the water conduit 42 is connected to the side surface of the pipe body 2 has been described. In this embodiment, a case in which the water conduit 742 is connected to the lower surface of the human hole 73 will be described.

  The human hole 73 is mainly composed of a main body portion 73a made of reinforced concrete, a bottom plate portion 73b formed integrally with the main body portion 73a, and an invert portion 73c made of concrete.

  The main body 73a is formed into a bottle shape in which a portion close to the ground surface is tapered, and an opening for connecting the pipe body 72 is formed at the lower portion of the side wall.

  The bottom plate portion 73b is an annular member having a hole in the center, and the inverted portion 73c is formed by the concrete cast on the hole and the top surface of the bottom plate portion 73b.

  Next, a construction method of the liquefaction countermeasure structure for the pipe 71 will be described.

  First, the ground is excavated in a groove shape until reaching the excavation line 53 of FIG. At this time, the place where the manhole 73 is installed is excavated deeper than the place where the pipe body 72 is installed, and crushed stone is spread on the bottom of the excavation to form the crushed stone foundation portion 73d.

  And the main-body part 73a of the prehole-made concrete human hole 73 manufactured beforehand in the factory etc. is installed on the crushed stone foundation part 73d.

  In addition, since a plurality of communication holes 741 and 741 are formed at predetermined positions of the bottom plate portion 73b formed integrally with the main body portion 73a, a water pipe is formed in the communication holes 741 and 741 from inside the human hole 73. 742 and 742 are inserted respectively.

  The water pipes 742 and 742 are arranged so that the lower end is pushed toward the lower ground of the human hole 73 until the lower end is embedded in the liquefied layer 52, and the upper end is exposed to a height exposed on the upper surface of the invert part 73c. The

  And concrete is cast in the state where the upper part of water pipes 742 and 742 protrudes on bottom slab part 73b, and invert part 73c is built. Further, check valves 744 and 744 are provided at the upper ends of the water pipes 742 and 742, respectively.

  Further, a tube body 72 is connected to the opening of the side wall of the human hole 73, and a backfill material 51 such as backfill soil is filled around the tube body 72 and the human hole 73.

  In this way, by extending the water pipes 742 and 742 directly under the human hole 73, the occurrence of liquefaction of the ground below the human hole 73 is suppressed as much as possible, and the floating of the human hole 73 during the earthquake is effectively prevented. can do.

  Other configurations and functions and effects are substantially the same as those in the above-described embodiment, and thus description thereof is omitted.

  Although the best embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment or example, and the design does not depart from the gist of the present invention. Such modifications are included in the present invention.

  For example, in the above-described embodiment, a cylindrical FRPM pipe is used as the pipe body 2. However, the present invention is not limited to this, and any material and any shape pipe body such as an FRP pipe, a steel pipe, or a concrete pipe may be used. Even if it exists, it is applicable to this invention.

  Moreover, in the said embodiment and Example, although the water flow pipes 42 and 742 were extended vertically downward, it is not limited to this, It is extended and extended so that it may spread diagonally downward, and it is a wide range. It is possible to prevent liquefaction of the liquefied layer 52, or to extend the taper obliquely downward from the pipe body 2 on both sides of the human hole 3 to intensively prevent liquefaction of the ground directly under the human hole 3. it can.

  Further, in the embodiment and the example described above, the case where the water pipes 42 and 742 are provided in the newly installed pipe lines 1 and 71 is described, but the present invention is not limited to this, and the water pipes are provided in the existing pipe lines. It can also be attached to make a liquefaction countermeasure structure.

  Moreover, in the said embodiment and Example, although the liquefaction countermeasure structure around the human hole 3 and 73 was demonstrated, it is not limited to this, It is the range in which only the tubular body 2 was arrange | positioned. The present invention can also be applied.

  Furthermore, in the said embodiment, although the case where the crushed stone was filled in the inside of the water flow pipe 42 as the filter material 43 was demonstrated, it is not limited to this, A fine mesh cover etc. which cannot pass sand etc. You may attach to the water flow pipe 42 as a filter material.

It is explanatory drawing explaining the structure of the liquefaction countermeasure structure of the pipe line of the best embodiment of this invention. (A) is sectional drawing explaining the structure which opened the communicating hole in the lower side surface of a pipe body, and provided the check valve in the upper end of a water pipe, (b) opened a communicating hole in the upper side surface of a pipe body, and a water pipe It is sectional drawing explaining the structure which extended the upper end of to the inside of a human hole. (A) is a partially cut side view for explaining the configuration of the lower end of the water pipe, and (b) is a partially cut side view for explaining a structure in which an opening is provided on the side surface of the water pipe. It is explanatory drawing explaining the structure of the liquefaction countermeasure structure of the pipe line of an Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pipe line 2 Tubing body 3 Human hole 41 Communication hole 42 Water communication pipe 422 Opening part 43 Filter material 44 Check valve 52 Liquefaction layer (lower ground)
71 Pipe 72 Pipe 73 Human hole 741 Communication hole 742 Water pipe 744 Check valve

Claims (3)

A liquefaction countermeasure structure for a pipe line that prevents at least one of the pipe body and a human hole connected to the pipe body when the ground around the pipe line has liquefied,
A communication hole that communicates the inside and outside of a pipe line that is provided in at least one outer shell of the pipe body and the human hole, a water pipe that extends from the communication hole to a lower ground of the pipe line, and the inside of the water pipe A liquefaction countermeasure structure for a pipeline characterized by comprising a filter material that prevents the passage of earth and sand.   The liquefaction countermeasure structure for a pipe according to claim 1, wherein a check valve is provided at an end of the water pipe inside the pipe. The liquefaction countermeasure structure for a pipe line according to claim 1 or 2, wherein a plurality of apertures are formed on a side surface of the water pipe.

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